Mg₂Ni_0.7M_0.3 (M=Al, Mn and Ti) alloys were prepared by solid phase sintering process. The phases and microstructure of the alloys were systematically characterized by XRD, SEM and STEM. It was found that Mg₃MNi₂ intermetallic compounds formed in Mg₂Ni_0.7M_0.3 alloys and coexisted with Mg and Mg₂Ni, and that radius of M atoms closer to that of Mg atom was more beneficial to the formation of Mg₃MNi₂. The hydrogen storage properties and corrosion resistance of Mg₂Ni_0.7M_0.3 alloys were investigated through Sievert and Tafel methods. Mg₂Ni_0.7M_0.3 alloys exhibited remarkably improved hydrogen absorption and desorption properties. Significantly reduced apparent dehydriding activation energy values of -46.12, -59.16 and -73.15 kJ/mol were achieved for Mg₂Ni_0.7Al_0.3, Mg₂Ni_0.7Mn_0.3 and Mg₂Ni_0.7Ti_0.3 alloys, respectively. The corrosion potential of Mg₂Ni_0.7M_0.3 alloys shifted to the positive position compared with Mg₂Ni alloy, e.g. there was a corrosion potential difference of 0.110 V between Mg₂Ni_0.7Al_0.3 alloy (-0.529 V) and Mg₂Ni (-0.639 V), showing improved anti-corrosion properties by the addition of Al, Mn and Ti.

Electrochemically promoted electroless plating (EPEP) was used for the application of pretreatment-free Ni-P coating on AM60B magnesium alloy at low temperatures and the obtained coating was characterized by SEM, AFM, EDS and XRD techniques. Compact, uniform, and medium-phosphorus Ni-P coating with mixed crystalline-amorphous microstructure was obtained by applying a cathodic current density of 4 mA/cm² at 50 °C. Also, island-like nickel clusters were deposited on the alloy surface under the same plating condition but without applying the cathodic current. In addition, the durability of the magnesium alloy against corrosion was strongly improved after plating via EPEP technique which was revealed by electrochemical examinations in 3.5% NaCl (mass fraction) corrosive electrolyte. The results of the electrochemical examinations were confirmed by microscopic observations. Thickness, microhardness, porosity and adhesive strength of the deposits were also qualified.

To avoid the defects caused by the hydrogen evolution and improve the corrosion and wear properties of the electroplated films in the traditional aqueous bath electrodeposition, a supercritical carbon dioxide (Sc-CO₂) emulsion was proposed to electrodeposite ternary nanocrystalline Co-Ni-P alloy films. Microstructure, corrosive and tribological properties of the Co-Ni-P films were investigated and compared with the ones electroplated by conventional method. The results show that the Co-Ni-P films produced with Sc-CO₂ assisted electrodeposition exhibit a more compact microstructure. The preferred orientation plane of hcp (110) for the Co-Ni-P films produced in conventional aqueous bath is changed to be hcp (100) for the one prepared in emulsified Sc-CO₂ bath. The microhardness, corrosion resistance and tribological properties of the Co-Ni-P films are substantially improved with the assistance of Sc-CO₂ in the electrodeposition bath.

Single Ni-P and Ni-Mo-P coatings as well as duplex Ni-P/Ni-Mo-P coatings with the same compositions were prepared by electroless plating. The residual stresses of the coatings on the surface and cross sections were measured by nanoindentation and AFM analysis, and the corrosion behaviour of the coatings in 10% HCl solution was evaluated by electrochemical methods, to establish the correlation between the residual stresses and corrosion behaviour of the coatings. The results showed that the single Ni-P and duplex Ni-P/Ni-Mo-P coatings presented residual compressive stresses of 241 and 206 MPa respectively, while the single Ni-Mo-P coating exhibited a residual tensile stress of 257 MPa. The residual compressive stress impeded the growth of the pre-existing porosity in the coatings, protecting the integrity of the coating. The duplex Ni-P/Ni-Mo-P coatings had better corrosion resistance than their respective single coating. In addition, the stress states affect the corrosive form of coatings.

Ni-based composite coatings with a high content of tungsten carbides (Stelcar 65 composite coatings) were synthesized by plasma transferred arc (PTA) hardfacing. The welding parameters of Stelcar 65 composite coatings were optimized by orthogonal tests. The PTA welding parameters including welding current, powder feed rate and welding speed have significant influence on the tungsten carbide degradation. The values for the optimum welding current, powder feed rate and welding speed were determined to be 100 A, 25 g/min and 40 mm/min, respectively. The produced WC/Ni-based composite coatings were crack- and degradation-free. The microstructure of deposited layers, as well as the microstructure and microhardness of the optimal coating were further analyzed.

First principles calculation and quasi-harmonic Debye model were used to obtain more physical properties of zirconium carbide under high temperature and high pressure. The results show that the B1 structure of ZrC is energetically more favorable with lower heat of formation than the B2 structure, and that mechanical instability and positive heat of formation induce the inexistence of the B2 structure at normal pressure. It is also found that the B1 structure would transform to the B2 structure under high pressure below the critical point of V/V₀=0.570. In addition, various thermodynamic and elastic properties of ZrC are obtained within the temperature range of 0-3000 K and the pressure range of 0-100 GPa. The calculated results not only are discussed and understood in terms of electronic structures, but also agree well with corresponding experimental data in the literature.

The effect of Zn dopant on the growth of cadmium oxide (CdO) nanostructures through a sonochemical method was investigated. The X-ray diffraction (XRD) patterns of the nanoparticles show CdO cubic structures for the produced samples. Field emission scanning electron microscope (FESEM) images reveal that morphologies of the samples change, when they are doped with Zn atoms, and their sizes reduce. Room temperature photoluminescence (PL) and UV-Vis spectrometers were used to study optical properties of the samples. Evaluation of optical properties indicates that different emission bands result from different transitions and the value of CdO energy band gap increases due to doping. Studies of electrical properties of the nanostructures demonstrate that Zn dopant enhances electrical conductivity and photocurrent generation as the result of light illumination on the nanostructures due to improved density of photo-generated carriers. Considering the obtained outcomes, Zn dopant can alter the physical property of the CdO nanostructures.

The reduced graphene oxide (rGO) supported cobalt oxide nanocatalysts were prepared by the conventional precipitation and hydrothermal method. The as-prepared rGO-Co₃O₄ was characterized by the XRD, Raman spectrum, SEM, TEM, N₂-sorption, UV-Vis, XPS and H₂-TPR measurements. The results show that the spinel cobalt oxide nanoparticles are highly fragmented on the rGO support and possess uniform particle size, and the as-prepared catalysts possess high specific surface area and narrow pore size distribution. The catalytic properties of the as-prepared rGO-Co₃O₄ catalysts for CO oxidation were evaluated through a continuous-flow fixed-bed microreactor-gas chromatograph system. The catalyst with 30% (mass fraction) reduced graphene oxide exhibits the highest activity for CO complete oxidation at 100 °C.

The discharge performance of Mg-Al-Pb-La anode was investigated by electrochemical techniques and compared with that of Mg-Al-Pb alloy. The results indicate that the Mg-Al-Pb-La anode provides enhanced corrosion resistance at open circle potential, and exhibits better discharge activity than the Mg-Al-Pb alloy. The utilization efficiency of Mg-Al-Pb-La anode is higher than that of commercial Mg-Al-Zn (AZ) and Mg-Al-Mn (AM) alloys. A single Mg-air battery with Mg-Al-Pb-La alloy as the anode and air as the cathode has an average discharge potential of 1.295 V and a discharge capacity of 1370 mA·h/g during discharge at 10 mA/cm², which is higher than that of batteries using Mg-Li anodes. The enhancement in discharge performance of the Mg-Al-Pb-La anode is caused by its modified microstructure, which reduces the self-corrosion and accelerates the spalling of oxidation products during battery discharge. Furthermore, the dissolution mechanism of Mg-Al-Pb-La anode during the discharge process was analyzed.

In order to improve the corrosion resistance of the Mg alloys, the superhydrophobic coatings on AZ31 Mg alloy were prepared by a two-step process of micro-arc oxidation treatment and superhydrophobic treatment in stearic acid ethanol solution. The effects of voltages, frequencies and treatment time on the contact angle of the superhydrophobic treated sample were investigated. The results showed that with increasing the voltage, frequency and treatment time, all of the contact angles of the superhydrophobic treated sample increased first, and then decreased, reaching the maximum values at 350 V, 1000 Hz and 5 min, respectively. The optimal superhydrophobic coating was mainly composed of MgO and Mg₂SiO₄ phases, with the pore diameter of ~900 nm, the thickness of ~6.86 μm and the contact angle of 156.96°. The corrosion current density of the superhydrophobic AZ31 sample decreased by three orders of magnitude, and the amount of hydrogen evolution decreased by 94.77% compared with that of the AZ31 substrate sample.

Faraday pseudocapacitors take both advantages of secondary battery with high energy density and supercapacitors with high power density, and electrode material is the key to determine the performance of Faraday pseudocapacitors. Transition metal oxides and nitrides, as the two main kinds of pseudocapacitor electrode materials, can enhance energy density while maintaining high power capability. Recent advances in designing nanostructured architectures and preparing composites with high specific surface areas based on transition metal oxides and nitrides, including ruthenium oxides, nickel oxides, manganese oxides, vanadium oxides, cobalt oxides, iridium oxides, titanium nitrides, vanadium nitrides, molybdenum nitrides and niobium nitrides, are addressed, which would provide important significances for deep researches on pseudocapacitor electrode materials.

A novel Bi₂S₃ microsphere was fabricated through one-pot urea-assisted solvothermal method. The synthesized Bi₂S₃ microsphere was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FT-IR) and thermal gravimetric analysis and differential thermal analysis (DTA-TG). Subsequently, the photocatalytic performances of Bi₂S₃ microsphere were evaluated by photocatalytic degradation of methyl orange (MO) simulation solution under visible-light irradiation. The results show that, Bi₂S₃ microsphere could be used as a potential cost-efficient catalysis for eliminating of methyl orange from aqueous solutions, whose degradation rate could reach 91.07% within 180 min. Besides, a tentative photocatalytic reaction mechanism was discussed according to the energy band position. Therefore, this work indicated a simplistic approach for the fabrication of visible-light responsive Bi₂S₃ microsphere photocatalyst, which can be used as a valuable candidate in solar energy conversion and environment pollution treatment.

Preparation of Zr₂Al₃C₄-Al₂O₃ in situ composites was investigated by self-propagating high-temperature synthesis (SHS) involving both aluminothermic reduction of ZrO₂ and chemical activation of PTFE (Teflon). The starting materials included ZrO₂, Al, carbon black and PTFE. In addition to the conventional SHS method, the experiments were conducted by a chemical-oven SHS (COSHS) route to thermally assist the synthesis reaction. The threshold amount of 2% (mass fraction) PTFE was required to induce self-sustaining combustion. When the conventional SHS scheme was utilized, due to low combustion temperatures between 1152 and 1272 °C and insufficient reaction time, the dominant carbide forming in the composite was ZrC instead of Zr₂Al₃C₄. On the other hand, the COSHS technique increased the combustion temperature of the reactant compact to about 1576 °C, lengthened the high-temperature duration for the reaction, and prevented Al vapor from escaping away. As a consequence, Zr₂Al₃C₄-Al₂O₃ composites with a small amount of Zr₃Al₃C₅ were obtained. The microstructure of the COSHS-derived product showed that plate-like Zr₂Al₃C₄ grains were about 2 μm in thickness and 10-30 μm in length, and most of them were closely stacked into a laminated configuration.

Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique. The effects of bath composition and electrodeposition condition on current efficiency, morphology, structure and hardness of the coatings were investigated and the optimum deposition condition was determined. It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate (SDS) concentration in the bath had a negligible effect on microhardness of the coatings, while they were effective on electrodeposition current efficiency. Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed (hcp) cobalt films and increased their microhardness without significant effect on current efficiency. Smoother and less defective coatings were also obtained from baths containing SDS and saccharin. The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle. Besides change of smooth morphology of the coatings to needle-shaped one, crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.

Two Fe-Al-based intermetallic aluminide coatings were fabricated on 430-SS (Fe-Cr) and 304-SS (Fe-Cr-Ni) substrates by pressure-assisted solid diffusion bonding with coating on pure Fe as control. The microstructure and intermetallic phases of the coatings were characterized by SEM, EDS and EBSD. A network of Cr₂Al₁₃ with matrix of Fe₄Al₁₃ was formed by inter-diffusing of Al with the substrates. The corrosion behavior of intermetallic coatings was investigated in 0.5 mol/L HCl solution by mass-loss, OCP, Tafel plot and EIS. It was found that corrosion resistance was greatly enhanced by dozens of times after the addition of Cr and Ni compared with that on pure Fe. The presence of cracks in the coating on 430-SS provided a pathway for corrosion media to penetrate to the substrate and accelerated the corrosion rate. Moreover, the corrosion product was analyzed by XRD, demonstrating that the addition of Cr and Ni facilitated the formation of more corrosion resistant phases, and therefore improved corrosion resistance.

Cu-1%Cr (mass fraction) and Cu-1%Cr-5% carbon nanotube (CNT) (mass fraction) nanocomposite powders were produced by mechanical alloying and consolidated by hot pressing. Then, nanocomposites were hot-rolled by the order of 50% reduction at 650 °C. The structure and microstructure were investigated by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Relative density, microhardness, thermal stability, electrical and wear properties were evaluated. Compared to the Cu-Cr sample, the relative density of Cu-Cr-CNT sample is greatly improved from 75% to near full density of 98% by hot rolling. Although electrical conductivity and microhardness increase in both Cu-Cr and Cu-Cr-CNT nanocomposites after hot rolling, the effect of hot rolling on the enhancement is more prominent in the presence of CNTs. The microhardness and electrical conductivity of hot-rolled Cu-Cr-CNT nanocomposite approach HV 175 and 68% (IACS), respectively. Also, hot rolling is more effective on thermal stability improvement of Cu-Cr-CNT nanocomposite compared to Cu-Cr composite. However, after hot rolling, both the friction coef？cient and wear loss of the Cu-Cr sample display higher reduction than those of Cu-Cr-CNT nanocomposite owing to different wear mechanisms. After hot rolling, friction coefficient and wear loss of Cu-Cr sample display variation of 25% and 62%, respectively.

A highly porous Ta-10%Nb alloy was successfully prepared for tissue engineering via the methods of the sponge impregnation and sintering techniques. The porous Ta-10%Nb alloy offers the capability of processing a pore size of 300-600 μm, a porosity of (68.0±0.41)%, and open porosity of (93.5±2.6)%. The alloy also shows desirable mechanical properties similar to those of cancellous bone with the elastic modulus and the comprehensive strength of (2.54±0.5) GPa and (83.43±2.5) MPa, respectively. The morphology of the pores in the porous Ta-Nb alloy shows a good interconnected three-dimension (3D) network open cell structure. It is also found that the rat MC3T3-E1 cell can well adhere, grow and proliferate on the porous Ta-Nb alloy. The interaction of the porous alloy on cells is attributed to its desirable pore structure, porosity and the great surface area. The advanced mechanical and biocompatible properties of the porous alloy indicate that this material has promising potential applications in tissue engineering.

Mg-5Zn-0.3Ca/nHA biocomposites were prepared from pure Mg, Zn, Ca and nano-hydroxyapatite (nHA) powders by powder metallurgy method. The effect of various mass fractions of nHA (1%, 2.5%, 5%) as reinforcement on the corrosion properties of Mg-5Zn-0.3Ca alloy was investigated. The corrosion resistance of biocomposite samples was investigated by immersion tests and electrochemical techniques in SBF solution. The results showed that the corrosion resistance of Mg alloy was improved by adding 1% and 2.5% nHA. Bioactive nHA motivated the formation of stable phosphate and carbonate layers on surface and improved corrosion resistance of nanocomposites. However, addition of large contents of nHA in Mg alloy as reinforcement increased the density of this precipitated layer, so gases produced from localized corrosion were accumulated underneath this layer and decreased its adhesiveness and lowered its corrosion resistance. Indirect cytotoxicity evaluation for Mg alloy and its nanocomposites also showed that their extraction was not toxic and nanocomposite with 1% nHA indicated almost similar behavior as negative control.

The Mg-6Al-4Zn alloy was fabricated by mechanical alloying (MA) and hot pressing to serve as biodegradable metal implant. The influence of addition of 1% Si (mass fraction) on the microstructure, mechanical properties and bio-corrosion behavior of Mg-6Al-1Zn alloy was studied using X-ray diffractometry, transmission electron microscopy, compression test, as well as immersion, electrochemical test and MTT assay. The results showed that the addition of 1% Si to Mg-6Al-1Zn alloy led to the formation of fine Mg₂Si phase with polygonal shape, and increased compressive strength, elongation and improved corrosion resistance. Furthermore, the cell viability of Saos-2 cells has been improved by addition of 1% Si to Mg-6Al-1Zn alloy. According to the results, the magnesium ions released in the methylthiazol tetrazolium (MTT) test have not shown any cell toxicity. All these indicated that the addition of 1% Si improved the properties of Mg-6Al-4Zn alloy for using as a biodegradable implant.

Titanium and its alloys are commonly used as dental and bone implant materials. Biomimetic coating of titanium surfaces could improve their osteoinductive properties. In this work, we have developed a novel osteogenic composite nanocoating for titanium surfaces, which provides a natural environment for facilitating adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs). Electrospinning was used to produce composite nanofiber coatings based on polycaprolactone (PCL), nano-hydroxyapatite (nHAp) and strontium ranelate (SrRan). Thus, four types of coatings, i.e., PCL, PCL/nHAp, PCL/SrRan, and PCL/nHAp/SrRan, were applied on titanium surfaces. To assess chemical, morphological and biological properties of the developed coatings, EDS, FTIR, XRD, XRF, SEM, AFM, in-vitro cytotoxicity and in-vitro hemocompatibility analyses were performed. Our findings have revealed that the composite nanocoatings were both cytocompatible and hemocompatible; thus PCL/HAp/SrRan composite nanofiber coating led to the highest cell viability. Osteogenic culture of MSCs on the nanocoatings led to the osteogenic differentiation of stem cells, confirmed by alkaline phosphatase activity and mineralization measurements. The findings support the notion that the proposed composite nanocoatings have the potential to promote new bone formation and enhance bone-implant integration.

High-purity porous Ti₃SiC₂ with a porosity of 54.3% was prepared by reactive synthesis and its oxidation behavior was evaluated under air in the temperature range from 400 to 1000 °C. Thermogravimetric analysis and differential scanning calorimetry (TG-DSC), scanning electron microscope (SEM), X-ray diffractometometry (XRD), energy dispersive spectrometer (EDS), Raman spectrum, BET surface area analysis, and pore-parameter testing were applied to the studies of the oxidation kinetics, phase composition, micro morphology, and porous structure parameters of porous Ti₃SiC₂ before and after oxidation. The results showed that the formation of TiO₂ oxidized products with different modifications was the primary factor influencing the oxidation resistance and structural stability of porous Ti₃SiC₂. Cracks were observed in the samples oxidized in the full temperature range of 400-1000 °C because of the growth stress and thermal stress. At 400-600 °C, anomalous oxidation with higher kinetics and the aberrant decrement in pore size and permeability were attributed to the occurrence of severe cracking caused by the formation of anatase TiO₂. At raised temperatures over 600 °C, the cracking phenomena were alleviated by the formation of rutile TiO₂, but the outward growth of the oxide scales detrimentally decreased the connectivity of porous Ti₃SiC₂.

The wetting of molten Sn-3.5Ag-0.5Cu alloy on the Ni-P(-SiC) coated SiC_p/Al substrates was investigated by electroless Ni plating process, and the microstructures of the coating and the interfacial behavior of wetting systems were analyzed. The SiC particles are evenly distributed in the coating and enveloped with Ni. No reaction layer is observed at the coating/SiC_p/Al composite interfaces. The contact angle increases from ~19° with the Ni-P coating to 29°, 43° and 113° with the corresponding Ni-P-3SiC, Ni-P-6SiC and Ni-P-9SiC coatings, respectively. An interaction layer containing Cu, Ni, Sn and P forms at the Sn-Ag-Cu/Ni-P-(0,3,6)SiC coated SiC_p/Al interfaces, and the Cu-Ni-Sn and Ni-Sn-P phases are detected in the interaction layer. Moreover, the molten Sn-Ag-Cu can penetrate into the Ni-P(-SiC) coatings through the Ni-P/SiC interface and dissolve them to contact the SiC_p/Al substrate.

An alternative solution for the direct formation of g-LiAlO₂ was presented by a modified combustion method, to apply it to rather simple systems, utilizing non-oxidizer compounds such as Al₂O₃ and LiOH, and urea as fuel. LiAlO₂ was prepared via non-stoichiometric 1:1, 1.5:1 and 2:1 of Li/Al molar ratios at 900 and 1000 °C for 5 min. Textural and structural characterization of γ-LiAlO₂ was performed. Also, the effect of different Li/Al molar ratios on material morphology and its stability before high gamma radiation gradients was evaluated. The results showed that the crystal structures of the obtained powders were γ-LiAlO₂ and a-LiAlO₂, depending on the Li/Al molar ratio. The results obtained demonstrate that g-LiAlO₂ microbricks, polyhedral and laminar shapes can be successfully synthesized with the proposed method and without any subsequent process. Additionally, gamma irradiation showed that the g-LiAlO₂ obtained does not decompose, forming only small amounts of Li₂CO₃. It can be established that the irradiation produces consolidation, which is not favourable for an efficient extraction of tritium. Finally, it could be demonstrated that nitrate precursors are not necessary in the combustion method to produce γ-LiAlO₂ with high purity.

The K_xNa_1-xNbO₃ nanopowders with cubic-like morphology and an average size of about 50 nm were synthesized by sol-gel auto-combustion method. And then, the ceramics were prepared and the phase transition, microstructure and electrical properties of the K_xNa_1-xNbO₃ ceramics were investigated. Pure perovskite phases of the K_xNa_1-xNbO₃ ceramics were confirmed by XRD patterns and the K_0.50Na_0.50NbO₃ ceramics show the coexistence of orthorhombic and monoclinic structures. SEM micrographs show that all samples have bimodal grain size distributions and the number of the small grains decrease with increasing K⁺ content in the bimodal grain size distribution system. The K_0.50Na_0.50NbO₃ ceramics with the uniform grain size and the maximum density show excellent electrical properties with ε_r=467.40, tan δ=0.020, d₃₃=128 pC/N and k_p=0.32 at the room temperature, demonstrating that the properties of the K_0.50Na_0.50NbO₃ powers prepared by sol-gel auto-combustion are excellent and the ceramics are promising lead-free piezoelectric materials.

Nickel oxide (NiO) hollow microspheres with hierarchical structure were fabricated through a process consisting of a self-assembling, hydrothermal reaction and calcination. The prepared NiO hollow microspheres composed of many nanoflakes, are about 2-3 μm in diameter. The length of the NiO flakes, having clear edges, is about 500-700 nm, while the thickness is only about 40-50 nm. This indicates that the NiO microspheres possess a hierarchical structure that can provide porous channels to facilitate the transmission of both electrons and electrolyte ions. NiO microspheres exhibit a high specific capacitance of about 1340 F/g at a current density of 1 A/g and high capacitance retention about 96.5% after 1000 cycles. What’s more, the conductive mechanism of nickel oxide for electrochemical capacitor electrodes was also studied.

In order to find the appropriate material to load selenium for higher performance of rechargeable Li-Se batteries, the resorcinol-formaldehyde resins derived monodisperse carbon spheres (RFCS)/Se composites were fabricated by the melting- diffusion method. The RFCS were obtained from initial carbonization of resorcinol-formaldehyde resins and subsequent KOH activation. Three kinds of samples of the RFCS/Se composites with different mass ratios were characterized by XRD, Raman spectroscopy, SEM, BET and EDS tests, which demonstrate that the samples with diverse mass fractions of selenium have distinct interior structure. The most suitable RFCS/Se composite is found to be the RFCS/Se-50 composite, which delivers a high reversible capacity of 643.9 mA·h/g after 100 cycles at current density of 0.2C.

To compare the hydrogen storage performances of as-milled REMg₁₁Ni-5MoS₂ (mass fraction) (RE=Y, Sm) alloys, which were catalyzed by MoS₂, the corresponding alloys were prepared. The hydrogen storage performaces of these alloys were measured by various methods, such as XRD, TEM, automatic Sievert apparatus, TG and DSC. The results reveal that both of the as-milled alloys exhibit a nanocrystalline and amorphous structure. The RE=Y alloy shows a larger hydrogen absorption capacity, faster hydriding rate, lower initial hydrogen desorption temperature, superior hydrogen desorption property, and lower hydrogen desorption activation energy, which is thought to be the reason of its better hydrogen storage kinetics, as compared with RE=Sm alloy.

The formation of bulk metallic glasses (BMGs) in the ternary Zr₅₆Co₂₈Al₁₆ and quaternary Zr₅₆Co_28-xCu_xAl₁₆ (x=2, 4, 5, 6, 7, mole fraction, %) glassy alloys was investigated via the copper mold suction casting method. The main purpose of this work was to locate the optimal BMG-forming composition for the quaternary ZrCo(Cu)Al alloys and to improve the plasticity of the parent alloy. The X-ray diffractometry (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) were used to investigate the glassy alloys structure and their glass forming ability (GFA). In addition, the compression test, microhardness, nano-indentation and scanning electron microscopy (SEM) were utilized to discuss the possible mechanisms involved in the enhanced plasticity achievement. The highest GFA among Cu-containing alloys was found for the Zr₅₆Co₂₂Cu₆Al₁₆ alloy, which was similar to that of the base alloy. Furthermore, the plasticity of the base alloy increased significantly from 3.3% to 6% for the Zr₅₆Co₂₂Cu₆Al₁₆ BMG. The variations in the plasticity and GFA of the alloys were discussed by considering the positive heat of mixing within Cu and Co elements.

Mg-based alloys received significant attention for temporary implant applications while, their applications have been limited by high degradation rate. Therefore, silver-zeolite doped hydroxyapatite (Ag-Zeo-HAp) coating was synthesized on TiO₂-coated Mg alloy by physical vapour deposition (PVD) assisted electrodeposition technique to decrease the degradation rate of Mg alloy. X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FE-SEM) images showed the formation of a uniform and compact layer of Ag-Zeo-HAp with a thickness of 15 μm on the TiO₂ film with a thickness of 1 μm. The potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) tests indicated that corrosion resistance of Mg-Ca alloy was considerably increased by the Ag-Zeo-HAp coating. The bioactivity test in the simulated body fluid (SBF) solution showed that a dense and homogeneous bonelike apatite layer was formed on the Ag-Zeo-HAp surface after 14 d. Investigation of antibacterial activity via disk diffusion and spread plate methods showed that the Ag-Zeo-HAp coating had a significantly larger inhibition zone (3.86 mm) towards Escherichia coli (E. coli) compared with the TiO₂-coated Mg alloy (2.61 mm). The Ag-Zeo-HAp coating showed high antibacterial performance, good bioactivity, and high corrosion resistance which make it a perfect coating material for biomedical applications.

Hydroxyapatite (HA) and strontium (Sr) incorporated HA coatings with different Sr contents were prepared on Mg-4Zn substrates by electrochemical deposition method. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electrochemical workstation were applied for the composition, phase constitution, morphology analyses and corrosion tests. The results reveal that the incorporation of Sr in coatings does not lead to dramatical change of functional groups and the crystal structure of the HA phase, but the crystal size and crystallinity decrease with increasing Sr content, which should be attributed to the lattice distortion and different occupancies of Sr and Ca ions. The 10SrHA@Mg-4Zn samples show the lowest corrosion current density and the highest corrosion potential, and also exhibit the lowest amount of hydrogen evolution among all coated samples.

Plasma electrolytic oxidation (PEO) was developed as a bond coat for air plasma sprayed (APS) nanostructure ZrO₂ as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method toward Escherichia coli (E. coli) bacterial pathogens, respectively. The lowest corrosion current density and the highest charge transfer resistance, phase angle and impedance modulus were observed for PEO/nano-ZrO₂ coated sample compared with those of PEO coated and bare Mg alloys. Nano-ZrO₂ top coat which has completely sealed PEO bond coat is able to considerably delay aggressive ions transportation towards Mg alloy surface and significantly enhances corrosion resistance of Mg alloy in simulated body fluid (SBF) solution. Moreover, higher antibacterial activity was also observed in PEO/nano-ZrO₂ coating against bacterial strains than that of the PEO coated and bare Mg alloys. This observation was attributed to the presence of ZrO₂ nanoparticles which decelerate E. coli growth as a result of E. coli membranes.

Perovskite is a versatile group of oxide materials allowing their properties to be tailored by composition towards specific requirements. LaAlO₃ was prepared to study and report its properties in the context of its potential in thermal barrier coatings (TBCs) technology. A citric acid method was used for synthesis and the perovskite structure was confirmed using XRD and FT-IR. Viscosity of the solution precursor was checked as well as the particle size by laser particle size analysis. Densification behavior of the material was followed by conventional sintering and by spark plasma sintering. Apparent porosity by the Archimedes method, thermal conductivity and thermal expansion coefficient were studied. Mechanical and fracture properties were measured at elevated temperatures up to 1300 °C. For samples sintered at 1200-1400 °C, coefficient of thermal expansion ranged from 5.5×10^-6 to 6.5×10^-6 K^-1 and thermal conductivity ranged between 2.2 and 3.4 W/(m？K). Elastic modulus and ultimate stress were measured at 1000-1300 °C, while by micro-indentation, fracture toughness was found to be 3 MPa·m^1/2. As the sintering temperature increased from 1200 to 1500 °C, significant densification from 3.21 to 5.81 g/cm³ was found, indicating that material annealing should be made at least at 1400 °C. Under this condition, negligible dimensional change in phase transition temperature of LaAlO₃ from the rhombohedral (R3c) to the ideal cubic (Pm3m) is found. Data reported in this work can be useful for comparing the mechanical and fracture behaviours of different TBCs developed involving LaAlO₃ as well as input for numerical simulations.

Ti/TiN multilayer film was deposited on uranium surface by arc ion plating technique to improve fretting wear behavior. The morphology, structure and element distribution of the film were measured by scanning electric microscopy (SEM), X-ray diffractometry (XRD) and Auger electron spectroscopy (AES). Fretting wear tests of uranium and Ti/TiN multilayer film were carried out using pin-on-disc configuration. The fretting tests of uranium and Ti/TiN multilayer film were carried out under normal load of 20 N and various displacement amplitudes ranging from 5 to 100 μm. With the increase of the displacement amplitude, the fretting changed from partial slip regime (PSR) to slip regime (SR). The coefficient of friction (COF) increased with the increase of displacement amplitude. The results indicated that the displacement amplitude had a strong effect on fretting wear behavior of the film. The damage of the film was very slight when the displacement amplitude was below 20 μm. The observations indicated that the delamination was the main wear mechanism of Ti/TiN multilayer film in PSR. The main wear mechanism of Ti/TiN multilayer film in SR was delamination and abrasive wear.

Nano/microcrystalline composite diamond films were deposited on the holes of WC-6%Co drawing dies by a two-step procedure using alternative carbon sources, i.e., methane for the microcrystalline diamond (MCD) layer and acetone for the nanocrystalline diamond (NCD) layer. Moreover, the monolayer methane-MCD and acetone-NCD coated drawing dies were fabricated as comparisons. The adhesion and wear rates of the diamond coated drawing dies were also tested by an inner hole polishing apparatus. Compared with mono-layer diamond coated drawing die, the composite diamond coated one exhibits better comprehensive performance, including higher adhesive strength and better wear resistance than the NCD one, and smoother surface (R_a=65.3 nm) than the MCD one (R_a=95.6 nm) after polishing at the same time. Compared with the NCD coated drawing die, the working lifetime of the composite diamond coated one is increased by nearly 20 times.

Color tunable quantum dots (QDs) based on the Cu, Mn, Ag co-doped ZnInS core and ZnS outer-shell were synthesized by using an eco-friendly method. Core-shell doped QDs with the average size of 3.85 nm were obtained by using a one-pot synthesis followed by a hot injection with n-dodecanethiol (DDT) and oleylamine (OLA) as stabilizers in oil phase. Cu, Mn and Ag ions were introduced as single-dopant or co-dopants during the synthesis, providing an effective means to control the emission color of the QDs. The as-synthesized QDs showed photoluminescence emission ranging from green (530 nm) to near-red (613 nm), adjusted by doping components, dopant concentration, and Zn/In ratio. Importantly, quasi-white emission has been achieved by controlling the concentration of co-doped metal ions (Mn, Cu and Ag). The primary results demonstrated the promising potential of co-doped QDs as alternative materials for future high quality white LED applications.

LiBH₄ was confined into activated charcoal (AC) by melt infiltration method (MI), and its effects on the hydrogen sorption properties were investigated. The N₂ adsorption results reveal that melt infiltration method can effectively incorporated LiBH₄ into AC. It can maintain the structural integrity of the scaffold and ensure the confinement effect. The nano-confined LiBH₄/AC starts to release hydrogen at around 190 °C, which is 160 °C lower than that of pure LiBH₄, and reaches a hydrogen desorption capacity of 13.6% at 400 °C. When rehydrogenated under the condition of 6 MPa H₂ and 350 °C, it has a reversible hydrogen storage capacity of 6%, while pure LiBH₄ shows almost no reversible hydrogen storage capacity under the same condition. Mass spectrometry analysis (MS) results suggest that no diborane or other impurity gases are released in the decomposition process. The apparent activation energy of dehydrogenation of LiBH₄ after confinement into AC decreases from 156.0 to 121.1 kJ/mol, which leads to the eminent enhancement of dehydrogenation kinetics of LiBH₄.

Different LiNi_0.8Co_0.15Al_0.05O₂ cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transformed infrared (FTIR) spectrum, X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge test and electrochemical impedance spectroscopy (EIS) were used to evaluate the elemental contents, structures, morphologies and electrochemical properties of samples. The results show that ethanol washing can remove effectively the synthetic residues LiOH/Li₂O on the freshly-prepared LiNi_0.8Co_0.15Al_0.05O₂ and make the sample much more resistant to H₂O and CO₂, without destroying its bulk structure, surface morphology and electrochemical performances. Moreover, the discharge specific capacity and cycle performance of LiNi_0.8Co_0.15Al_0.05O₂ after storage in air with a relative humidity of 80% for three months are improved by immediate ethanol washing.

Using the three-dimensional reticular nickel foam as experimental material, the sound absorption performance was investigated for several various multilayer structures in the frequency range of 2000-4000 Hz, which is aurally sensitive for human ears. The results showed that the 7.5 mm-thick foam sample, which was formed by piling of 5-layer foam plate (thickness: 1.5 mm; porosity: 96%; average pore-diameter: 0.65 mm) could exhibit an excellent sound absorption effect at 4000 Hz, with the absorption coefficient about 0.8. Constituting alternate air gap with the total thickness of about 18.5 mm can greatly improve the absorption performance at relatively low frequencies of 2000-3150 Hz, with the absorption coefficient up to about 0.5 or more. In addition, the research showed that alternate piling up the perforated plate inside the foam plates can also achieve a quite good effect of sound absorption at relatively low frequencies.

Metal injection molding (MIM) was applied to fabricating Ti-22Nb (mass fraction, %) and commercially-pure Ti (CP-Ti, selected as reference) discs. As references, arc-melted and polished Ti-22Nb discs were employed. The surface topography and cytocompatibility were comparatively assessed on each configuration by microscopic analysis using confocal laser scanning microscopy and scanning electron microscopy and adhesion and viability tests. The results reveal that micron-scale roughness could be obtained via MIM process, and using blended Ti and Nb elemental powders instead of only Ti powder as raw materials leads to much higher surface roughness and surface area ratio. None of the three materials shows cytotoxicity, and the adhesion of human primary cells seems to be increased on the MIM Ti-22Nb specimens, especially around the closed-pores on the surface.

Effects of cold rolling followed by annealing on microstructural evolution and superelastic properties of the Ti₅₀Ni₄₈Co₂ shape memory alloy were investigated. Results showed that during cold rolling, the alloy microstructure evolved through six basic stages including stress-induced martensite transformation and plastic deformation of martensite, deformation twinning, accumulation of dislocations along twin and variant boundaries in martensite, nanocrystallization, amorphization and reverse transformation of martensite to austenite. After annealing at 400 °C for 1 h, the amorphous phase formed in the cold-rolled specimens was completely crystallized and an entirely nanocrystalline structure was achieved. The value of stress level of the upper plateau in this nanocrystalline alloy was measured as high as 730 MPa which was significantly higher than that of the coarse-grained Ni₅₀Ti₅₀ and Ti₅₀Ni₄₈Co₂ alloys. Moreover, the nanocrystalline Ti₅₀Ni₄₈Co₂ alloy had a high damping capacity and considerable efficiency for energy storage.